Centrifuges with retainers, retainers, and bottle stoppers for use therewith



May 19, 1964 CENTRIFUGES WITH R Filed July 21, 1961 FIGZ ETAINERS, RETAINERS, AND BOTTL STOPPERS FOR USE THEREWITH D F MITCHELL ETAL 3 Sheets-Sheet 1 INVENTORS DAVID E MITCHELL RICHARD W. SCHMADER ATTO RN ZY May 19, 1964 D F. MITCHELL ETAL Inn.

H RETAINERS, RETAINERS, AND BOTTL STOPPERS FOR USE THEREWITH 3 Sheets-Sheet 2 v INVENTORS DAVID E MITCHELL RICHARD w. SCHMADER y 1964 D. F. MITCHELL ETAL 3,133,832

CENTRIFUGES WITH RETAINERS, RETAINERS, AND BOTTLE STOPPERS FOR USE THEREWITH Filed July 21, 1961 3 Sheets-Sheet 3 I VENTORS DAVID F. Ml

CHELL RICHARD W. SCHMADER FIG] BY ATTORNEY Patented May 19, 1964 3,133,882 CENTRIFUGES WITH RETAINERS, RETAINERS, AND BOTTLE STOPPERS FOR USE THEREWITH David F. Mitchell, Tewlrshury, and Richard W. Schmader,

Winchester, Mass, assignors to International Equipment Company, Boston, Mass, a corporation of Massachusetts Filed July 21, 1951, Ser. No. 125,782

Claims. (Cl. 233-26) The present invention relates to centrifuges provided with retainers for use in preventing damaging distortions of plastic bottles in use, to the retainers, and to bottle stoppers useable with certain of such retainers.

It is common practice to provide a centrifuge head with a series of arcuately spaced, bottle-receiving cavities that have their axes outwardly and downwardly inclined from the bottom of a central, upwardly opening cavity. While stainless steel bottles are available for use with such heads, their cost is such that it is a much wider practice to centrifuge the material in plastic bottles.

Such bottles, While considerably less costly than those of stainless steel, have features that are decidedly dis advantageous in that they are flexible and cold flow and hence distort, in a centrifugal field, unless suitably confined. As it is the usual practice to have the stoppered ends of the bottles protrude from their cavities, the distortion of the bottles, at least above rather low centrifuge speeds, often results in bottle ruptures or their permanent distortion and it is the elimination of these objectionable consequences that are the general objectives of the present invention.

In accordance with the invention, this objective is attained by providing each head with a retainer in the form of an insert which is centered within the central head cavity and provided with a series of seats, one for each bottle-receiving recess and shaped and dimensioned to overlie at least a part of the mouth of a bottle positioned in the subjacent bottle cavity and, where the bottle protrudes from such a cavity, the seat includes an arcuate portion that functions to back the outer portion of the protruding bottle part and is contoured to correspond to the shape thereof.

The retainer-establishing insert is preferably cylindrical and dimensioned to fit the central, upwardly opening head recess, and, in one embodiment of the invention, the retainer seats partially overlie the stoppered ends of the bottles while, in another embodiment, the stoppered bottle ends are positively anchored to the retainer.

It is preferred that the retainers be anchored to the heads and this may be done by locking each retainer to its head, by providing a head cover that is locked to a head in engagement with the upper face of the retainer seated therein, or by using both expedients.

In the accompanying drawings, there are shown illusF trative embodiments of the invention from which these and other of its objectives, novel features, and advantages will be readily apparent.

In the drawings:

FIGURE 1 is a vertical section through a centifuge head with a partly sectioned, stoppered bottle in one of its bottle receiving cavities and with a retainer in accordance with the invention in place,

FIGURE 2 is a bottom plan view of the retainer,

FIGURES 3 and 4 are, respectively, bottom and top perspective views thereof,

FIGURE 5 is a view, similar to FIGURE 1, illustrating a retainer and bottle stopper construction in accordance with another embodiment of the invention,

FIGURE 6 is a partly sectioned, edge view of the retainer of FIGURE 5, and

FIGURE 7 is a bottom plan view thereof.

A typical centrifuge head is generally indicated at 10 and is shown as having a central, upwardly opening, cylindrical cavity 11 and a series of arcuately spaced, bottle-receiving cavities 12 opening into the bottom thereof and having their axes outwardly and downwardly inclined. At the upper end of the cavity 11, there is a glrfioved shoulder 11A for a cover C shown only in FIG- A conventional plastic bottle is generally indicated at 13 and is shown as having a shoulder 14 defining a neck 15 with its mouth closed as by an expansible stopper, generally indicated at 16. The stopper 16 comprises a centrally recessed cap 17 fitting the mouth of the bottle 13 and provided with a flange 18 overlying the lip thereof. A flanged keeper 19 fits freely in the mouth of the bottle and confines an annular, compressible seal 20 between it and the cap 17. The keeper 19 has a threaded stem 21 extending through the cap 17 and provided with a cap-engaging nut 22 by the rotation of which the seal 26 may be compressed to render it eflFective due to the resulting expansion thereof, or released to enable the stopper 16 to be removed.

The bottle 13 is shown as protruding from its cavity 12 from a zone near but below its shoulder 14. As a consequence, as the rate of rotation of the head increases, the force exerted on the outer portion of the protruding bottle part increases until it is distorted towards the wall of the cavity 11. As the bottle-receiving cavities are, in the illustrative embodiment of the invention, internally tangent to the cavity 11, their junctions therewith define angular projections 23 so that the danger of a bottle run turing, as its wall is forced over the edge of its cavity 11 on either side of such a projection, is substantial even at moderate centrifuge speeds. At the same time, the wall of the bottle 13 on the inner side thereof, tends to collapse, due to the displacement of the liquid, as indicated by the dot-dash line 24 and the outer portion of the stopper 16 is urged upwardly while the inner portion is pulled downwardly by such partial collapse.

In accordance with the invention, a retainer, generally indicated at 25, is provided to prevent such objectionable distortions of the bottles 13. The retainer 25 is shown as a ring whose outer surface 26 is cylindrical and dimensioned to fit the cavity 11. The inner surface of the retainer is provided with a series of arcuately spaced, arcuate, recessed seats 27, one for each bottle receiving cavity 12 and shaped and dimensioned to overlie part of the stopper 16, and being shown as disposed in a plane at right angles to the axes of the subject bottle cavity 12. Each seat 27 has an arcuate portion 28 contoured as required by the shape of the protruding part of the bottle thus to serve as a backing for the outer portion therefor. The seats and their portions 28, preferably, are about in extent and each is centered along a line which, when the retainer is in use, is an extension of the axis of the subjacent bottle-receiving cavity.

With such a retainer, the shoulder zone of a plastic bottle is firmly backed against damaging distortion and the outer portion of the stopper 16 is confined. The bottle is still, however, responsive to the distorting effects that are due to liquid displacement so that the retainer is subjected to lifting pressures which can be objectionable at speeds that, while substantially higher than those at which unrestrained bottles are dangerously distorted, are in a relatively moderate speed range. For that reason, the retainer is shown as being locked to the head 10 as by generally indicated locks 30. The locks 30 are shown as of a type including sockets 31 in the wall of the head 10. Plungers 32 are yieldably held in bores 33 against entry into respective ones of the sockets 31 by springs 34 which are operative until their holding force is overcome by centrifugal force. The plungers 32 then seat in the 3 sockets 31 to prevent movement of the retainer relative to the head.

In FIGURES through 7, there is shown another embodiment of the invention which is well adapted to meet the requirements of even higher centrifuge speeds. The generally indicated retainer 35 is similar to the retainer 25 in that it is ring-shaped and its outer surface 36 is cylindrical and dimensioned to fit the head cavity 11. The retainer 35 has a series of recessed seats, generally indicated at 37, and these are arcuately spaced. There is one such seat 37 for each bottle cavity 12 and it is dimensioned to overlie the stoppered end of a bottle 13 positioned therein and is in a plane at right angles to the axis of the subjacent cavity 12. As the bottles 13 are dimensioned to protrude from the cavities 12, each seat has an arcuate portion 38, shown as somewhat more than 180 in extent, to serve as a backing for the outer portion of a protruding bottle part and contoured to correspond to the shape thereof. The inner portion of each recessed seat 37 fits over the inner portion of each stoppered bottle and the under surface of the retainer 38 is shown as annularly grooved as at 39 to provide an annular wall 40 tangent to each recess 37 and in parallel with the axis of the head.

The bottle stopper 16A is similar to the stopper 16 except that its threaded stem 21A is of sufficient length to pass upwardly through a bore 41 with which each seat 37 is formed and which is disposed, when the retainer is in use, as a continuation of the axis of the subjacent bottle cavity 12. The diameter of the bores 41 is sufficient larger than that of the stems 21A to permit the retainer 35 to be seated in the cavity 11 of the head with the stems 21A extending freely upwardly through the upper retainer surface. The bores 41 open through the face 42 of an annular channel 43, the face 42 of which being parallel with respect to each seat 37. The bore 41 is shown as receiving a sleeve-like nut 44 threaded on the stem 21A with its flange 45 engaging the face 42 and holding the stoppered mouth of the subjacent bottle against the overlying seat. By this arrangement, the distorting forces exerted on each bottle are largely cancelled by those exerted on the others.

In high centrifugal fields, liquid displacement exerts sufficient upward thrust to make the positive anchoring of the retainers against upward movement desirable. Such anchoring may be elfected by locking the retainers to their heads as has been discussed in connection with the retainer illustrated by FIGURES 1 through 4 but in FIG- URE 5, such anchoring is shown as effected as by means of the cover C with which heads of the type herein shown are commonly provided.

As shown in FIGURE 5, the cover C has a central opening 46 receiving the stem 47 and an O-ring 48 which is compressed against the stem 47 by the stern knob 49. The cover C is held on the stem 47 as by a retaining ring 50. At the lower end of the stem 47 there is a shoulder 51 and an axial projection 52 threaded for entry into the threaded bore 53 of an adaptor 54 attachable to the drive shaft (not shown) as by a pin 55 and provided with a flange 56 through which extend screws 57 anchoring the adaptor 54 to the head 10. The upper end of the adaptor 54 is recessed as at 58 to provide a seat for the seal 59 engageable by the shouldered end of the stem 47. By this arrangement, the projection 52 may be threaded into the adaptor 54 to bring the cover C against its seat 11A and compressing the O-ring 60. It will be noted that the retainer 38 is shown as having a central hub portion 61 which projects for engagement by the attached cover C.

We claim:

1. In combination, a centrifuge head of the type having a central, upwardly opening, cylindrical cavity and for use with plastic bottles each having a straight sided cylindrical container part and a cap of smaller cross sectional area, said head having a plurality of smaller, bottle-receiving, cylindrical cavities opening into the bottom of the central cavity and having their axes outwardly and downwardly inclined, each bottle receiving cavity being straight sided and dimensioned to snugly receive such a bottle with its capped end protruding into said central cavity, and a cylindrical retainer dimensioned to fit snugly within said central cavity and to be centered thereby, said retainer including a plurality of downwardly opening seats, one above each bottle receiving cavity, each seat including arcuate portions whose axes are outwardly and downwardly inclined with each in alinement with the axis of an appropriate one of said bottle receiving cavities, the arcuate portions of each seat being dimensioned to snugly receive the outwardly disposed surfaces of a capped end of a bottle supported in the subjacent bottle receiving cavity in a zone inclusive of the junction of the central cavity with each bottle receiving cavity and of an arcuate extent opposing distortion of that bottle while in a centrifugal field.

2. The combination of claim 1 and centrifugally operated locking means between the retainer and the wall of the head defined by its central cavity holding the retainer against upward movement during centrifugation.

3. The combination of claim 1 in which the retainer has a central, upwardly opening hub portion, and locking means in the form of a cover closing the central cavity and seated against the upper surface of the hub portion of the retainer, and an axial cover attaching member extending downwardly through the cover and hub portion and threaded into the head.

4. In combination, a plurality of plastic bottles each including a straight sided, open-ended, cylindrical container part and a stopper within said open end, each stopper including an axially protruding bolt, a centrifugal head of the type having a central, upwardly opening cylindrical cavity having a plurality of smaller, bottle receiving, cylindrical cavities opening into the cylindrical cavity and having their axes outwardly and downwardly inclined, each bottle receiving cavity being straight sided and dimensioned to snugly receive one of said bottles with its capped end protruding into said central cavity, and a cylindrical retainer dimensioned to fit snugly and be seated within said central cavity and to be centered thereby, said retainer including a plurality of downwardly opening seats, one above each bottle receiving cavity and including arcuate portions whose axes are outwardly and downwardly inclined with each in alinement with the axis of an appropriate one of said bottle receiving cavities, the arcuate portions of each seat being dimensioned to snugly receive the outwardly disposed portions of the capped end of the bottle supported in the subjacent bottle receiving cavity in a zone exclusive of the junction of the central cavity with each bottle receiving cavity and of an arcuate extent opposing distortions of that bottle while in a centrifugal field, each seat having a bore opening upwardly through said retainer at such an angle and of such size that the stopper bolt of the subjacent bottle passes therethrough as said retainer is seated, each stopper bolt being of sulficient length to extend upwardly therethrough, and an anchor on each bolt and engaging the upper surface of said retainer, and plugging the bore through which that bolt extends to prevent movement thereof.

5. In combination, a centrifugal head of the type having a central, upwardly opening, cylindrical cavity and for use with plastic bottles having a straight sided, openended, cylindrical container part and a stopper in its open end and having an axially disposed, protruding bolt, said head having a plurality of smaller, cylindrical bottle receiving cavities opening into the cylindrical cavity and having their axes outwardly and downwardly inclined, each bottle receiving cavity being straight sided and dimensioned to snugly receive such a bottle with its capped end protruding into said central cavity, and a cylindrical retainer dimensioned to fit snugly within said central cavity and to be centered thereby, said retainer including a plurality of downwardly opening seats, one above each bottle receiving cavity, each seat including arcuate portions Whose axes are outwardly and downwardly inclined with each in alinernent with the axis of an appropriate one of said bottle receiving cavities, the arcuate portions of each seat being dimensioned to snugly receive the capped end of a bottle in the subjacent bottle receiving cavity in a zone inclusive of the junction of the central cavity with each bottle receiving cavity and of an arcuate extent opposing distortion of that bottle While in a centrifugal field, each seat having a bore opening upwardly through said retainer disposed and dimensioned to receive a stopper bolt as said retainer is seated.

References Cited in the file of this patent UNITED STATES PATENTS Larsen Nov. 19, 1929 Grebmeier Aug. 17, 1948 MacLeod Nov. 4, 1952 Allen et al. Jan. 11, 1955 Pickels et a1 Mar. 24, 1959 Blum July 14, 1959 Piemonte et a1. Jan. 1, 1963 FOREIGN PATENTS Great Britain Apr. 6, 1961 

1. IN COMBINATION, A CENTRIFUGE HEAD OF THE TYPE HAVING A CENTRAL, UPWARDLY OPENING, CYLINDRICAL CAVITY AND FOR USE WITH PLASTIC BOTTLES EACH HAVING A STRAIGHT SIDED CYLINDRICAL CONTAINER PART AND A CAP OF SMALLER CROSS SECTIONAL AREA, SAID HEAD HAVING A PLURALITY OF SMALLER, BOTTLE-RECEIVING, CYLINDRICAL CAVITIES OPENING INTO THE BOTTOM OF THE CENTRAL CAVITY AND HAVING THEIR OWN AXES OUTWARDLY AND DOWNWARDLY INCLINED, EACH BOTTLE RECEIVING CAVITY BEING STRAIGHT SIDED AND DIMENSIONED TO SNUGLY RECEIVE SUCH A BOTTLE WITH ITS CAPPED END PROTRUDING INTO SAID CENTRAL CAVITY, AND A CYLINDRICAL RETAINER DIMENSIONED TO FIT SNUGLY WITHIN SAID CENTRAL CAVITY AND TO BE CENTERED THEREBY, SAID RETAINER INCLUDING A PLURALITY OF DOWNWARDLY OPENING SEATS, ONE ABOVE EACH BOTTLE RECEIVING CAVITY, EACH SEAT INCLUDING ARCUATE PORTIONS WHOSE AXES ARE OUTWARDLY AND DOWNWARDLY INCLINED WITH EACH IN ALINEMENT WITH THE AXIS OF AN APPROPRIATE ONE OF SAID BOTTLE RECEIVING CAVITIES, THE ARCUATE PORTIONS OF EACH SEAT BEING DIMENSIONED TO SNUGLY RECEIVE THE OUTWARDLY DISPOSED SURFACES OF A CAPPED END OF A BOTTLE SUPPORTED IN THE SUBJACENT BOTTLE RECEIVING CAVITY IN A ZONE INCLUSIVE OF THE JUNCTION OF THE CENTRAL CAVITY WITH EACH BOTTLE RECEIVING CAVITY AND OF AN ARCUATE EXTENT OPPOSING DISTORTION OF THAT BOTTLE WHILE IN A CENTRIFUGAL FIELD. 